Allow dynamic models created with create_model() to be used as annotations in the Mypy plugin#12879
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Viicos merged 4 commits intopydantic:mainfrom Mar 7, 2026
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Implement a dynamic class hook so that variables assigned from create_model() are recognized by mypy as proper class types rather than plain variables. This allows them to be used in type annotations, isinstance() checks, and as function parameter types. The hook handles the __base__ keyword argument so the synthetic class inherits from the correct base when specified.
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Please also apply the following diff:
diff --git a/tests/mypy/modules/create_model_var.py b/tests/mypy/modules/create_model_var.py
new file mode 100644
index 000000000..cc2c72b1b
--- /dev/null
+++ b/tests/mypy/modules/create_model_var.py
@@ -0,0 +1,12 @@
+from pydantic import BaseModel, create_model
+
+
+class Model(BaseModel):
+ a: int
+
+
+SubModel = create_model('SubModel', __base__=Model)
+
+
+class Main(BaseModel):
+ sub: SubModel
diff --git a/tests/mypy/outputs/mypy-plugin_ini/create_model_var.py b/tests/mypy/outputs/mypy-plugin_ini/create_model_var.py
new file mode 100644
index 000000000..cc2c72b1b
--- /dev/null
+++ b/tests/mypy/outputs/mypy-plugin_ini/create_model_var.py
@@ -0,0 +1,12 @@
+from pydantic import BaseModel, create_model
+
+
+class Model(BaseModel):
+ a: int
+
+
+SubModel = create_model('SubModel', __base__=Model)
+
+
+class Main(BaseModel):
+ sub: SubModel
diff --git a/tests/mypy/test_mypy.py b/tests/mypy/test_mypy.py
index 679d184f9..4fa052776 100644
--- a/tests/mypy/test_mypy.py
+++ b/tests/mypy/test_mypy.py
@@ -109,6 +109,7 @@ cases: list[ParameterSet | tuple[str, str]] = [
('mypy-plugin.ini', 'root_models.py'),
('mypy-plugin.ini', 'plugin_strict_fields.py'),
('mypy-plugin.ini', 'final_with_default.py'),
+ ('mypy-plugin.ini', 'create_model_var.py'),
('mypy-plugin-strict-no-any.ini', 'dataclass_no_any.py'),
('mypy-plugin-very-strict.ini', 'metaclass_args.py'),
('pyproject-plugin-no-strict-optional.toml', 'no_strict_optional.py'),```
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Viicos
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get_dynamic_class_hook() for create_model() in mypy plugin
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Thanks for the feedback! Updated: Added test cases for create_model_var as requested. Let me know if there's anything else. |
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Fix typo where CREATE_MODEL_FULLNAMES (plural) was used instead of CREATE_MODEL_FULLNAME (singular), which was causing F821 lint errors.
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get_dynamic_class_hook() for create_model() in mypy plugincreate_model() to be used as annotations in the Mypy plugin
Viicos
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Mar 7, 2026
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Change Summary
Add a
get_dynamic_class_hookto the pydantic mypy plugin so that variables assigned fromcreate_model()are recognized as proper class types. This allows them to be used in type annotations,isinstance()checks, and as function parameter types without mypy errors.The hook also handles the
__base__keyword argument so the synthetic class inherits from the correct base when specified.Related issue number
fix #12031
Checklist
make lintandmake format